Treating molten metals with calcium-copper alloys



Patented Nov. 24, 1925.

- UNITED ST s PATENT OFFICE.

wrrmam a. HARVEY, on nmeananns; new roan, AssIeNon TO AMERICAN new YORK;

'rnnarrme Momma ariam wtrr'ncnncmn-corrnn ALLOYS.

No Drawing To (ill whom it may concern Be it known that WILLIAM Niagara Falls, inthe county of; Niagara and State of New York. has invented oer-T tain new and usefullm rovements in Treat-- ing Molten Metals with Calcium-Copper Alloys, of whicli'- the following is a specification.

My invention relates to the refining and alloying ofthe same.

One of the objects of'the invention is the provision of'fi'a copper calcium alloy which may be added'to molten alloys,

, where Jit'ie 'eithervdesirable or not objec-x tionable to add asmallfquantity of copper cium was to be added to such alloys in an unalloyed condition considerable difficulty would be experienced in forcing it beneath, the surface of the molten alloys. Furthermore, metalliccalcium as commercially available varies greatly in purity aildJ oxidizes rapidly in air, so that its usein' this form is attended by much diiliculty.

Calcium is also a very vigorous deoxidizing agent and when it is added to molten metal in an undiluted form, the reaction 'which takes place may be so violent as to project the molten metal out of the holding rece tacle.

etallic calcium has a melting point of.

about 805 degrees C., whereas the calcium copper alloy which l use has a melting po1nt much below this. This is a very definite aid when deoxidizing a pot of metal, for when this alloy is used, on account of its much lower'melting point, it very quickly melts and is rapidly andthoroughly disseminated throughout the metal.

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Calcium copper in the form of an alloy containing from approximately 40-60% of calcium imparts to the treated metal all the desirable features of metallic calcium with the added advantage that it is easy to apply. it is important in'all deoxidizing work to v "HARVEY, citizen of the United States, residing at to the treatment of j molten metals and alloys and particularly are the aluminum .Application area September '10, 1921. Serial No. 499,184

add theproper quantities of the deoxidiz ing agent as overdosing often produces 1n ur1ousqual1t1es. When deoxidizing by 'means of the copper calcium; alloy herein specified the amount of calcium to be added can be more closely regulated.

The proportions of metals found most desirable forfthis use are calcium and 50% copper, although the perce'ntagesmay vary in each case from 40-60. An alloy of these proportions is very brittle, which allows itto be easily broken into a convenientsize and into an exact weight when he added to apot of metal. The specific grav ty of. the '50'50 alloy is 2.8 and it has a meltingpoint 0% 630 degrees-C.

Ordinary aluminum bronze containing ten per cent aluminum, which is one of the alloys particularly intended to be treated with the coppercalcium alloy, has a specific gravity of7'.3 and amelting point of about 1020-1030 degrees 0. The addition of a 50-50'cop er calcium alloy to this metal has their vantage of a muchlower meltingpoint-than the aluminum bronze and also oif a sufficiently higher s ecific gravity than calcium so that such aloy is more readily incorporated into the metal to be deoxidized.

In carrying out the process, I utilize a carbon lined furnace, in-which the bottom of the furnace is the negative pole. Anode bus bars "are ;suspended over the furnace and from them, de end into the furnace, a suitable'number 0 carbon electrodes.

In startinga furnace, a suitable quantity of preferably'flat pieces of solid copper is placed upon the carbonbottom. Any scrap MAGNESIUM GOBIBOBA'IION', OF N BALLS, NEW YORK, A CORPORATION OF copper-calcium alloy from previous runs" may be put in at this'time, as an aid to the starting of the furnace, by more quickly lowerin the melting point of the cathode. Using ectric current, preferably alternating, arcs are struck upon these copper pieces, a favorable voltage for this operation being in the neighborhood of 55. Dried calcium chloride, from which the .water of crystallization has been removed by previous fusion,is fed into the furnace around these arcs, and a molten bath very quickly 'results. The current is then carried through this molten bath and the arcs disap ear.

Hill

This operation of melting is continue unpreliminary stage, direct current is then I ode til a suitable depth of bath is attained. If alternating current has been usedi-in the substituted. Electrolysis starts at once as is made evident by a very vigorous boiling action around the anodes which is caused by chlorine gas, which is the product at the anode. Metallic calcium deposits on the solid pieces of copper, which. act as a cathode. A considerable quantity of calcium is taken up and'alloys with the copper before the melting point of the alloy is reached. As the copper-continues to absorb calcium, the melting point of the alloy is gradually reduced and eventually the oathbecomes molten. Suitable uatities of dried calcium chloride are adde at in tervals as the level of the electrolyte lowers.

Metallic copper is added at intervals and with the purpose of keeping the calcium content in the molten cathode, during most of the period of production, at from 20-30% or an average of approximately After the last addition of copper has been made, the furnace is then run for a period of time, until the alloy has a specific gravity of about 2.8 which corresponds to about 50% of calcium. The furnace is then tapped. The best operating temperature for carrying out the process is approxi-.

mately from 77 5-825 degrees C. The particular advantages derived from such proportions in the use of this alloy for the particular purposes herein specified give to an alloy of substantially these proportions a decided technical advantage.

From the above description, it will be apparent that I have produced an alloy which accomplishes the purposes for which intended and while I have set forth specific proportions and. uses for the same, it

will be understood that I reserve the right to all changes properly falling within the spirit and scope of the appended claims.

I claim: a

1. The method of deoxidizing aluminum bronze comprising adding to the molten metal .an alloy of calcium and copper in such ro ortions that the alloy 'is brittle and w ic has a-melting point substantially less than that of the treated metal.

2. The method of alloying copper -with an aluminum containing metal and simultaneously deoxidizing the said metal, comprising treatin the said metal with an alloy of calcium an copper in such proportions that the alloyis brittle and has a melting point less than that of the treated metal. 1

3: The method of deoxidizing aluminum bronze comprising adding to the molten metal an alloy of calcium and copper containing from 40-60% calcium.

4. The method of deoxidizing aluminum bronze comprising treating the molten metal with an alloy containing approximately of calcium and 50% of copper.

In testimon whereof I aflix my signature.

ILLIAM. G. HARVEY. 

